Apparatus and methods for reducing unintended transport of data from power distribution systems using layered power filters

ABSTRACT

In some embodiments, a method includes receiving, at a circuit board, a power from a power supply. The method further includes filtering, at the circuit board and via a power filter having at least three choke filters, the power to produce a filtered power. The method further includes dividing, at a first portion of a circuit on the circuit board, a power associated with the filtered power into a first power and a second power, a characteristic of the first power differing from a characteristic of the second power by a factor of at least 1.5 or at most one half.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.17/091,788, filed Nov. 6, 2020, entitled “Apparatus and Methods forReducing Unintended Transport of Data from Power Distribution SystemsUsing Layered Power Filters,” now U.S. Pat. No. 11,291,117), which is acontinuation of U.S. patent application Ser. No. 16/938,212, filed Jul.24, 2020 and entitled “Apparatus and Methods for Reducing UnintendedTransport of Data from Power Distribution Systems Using Layered PowerFilters,” now U.S. Pat. No. 10,869,394, which claims priority to and thebenefit of U.S. Patent Application No. 62/942,432, filed Dec. 2, 2019and entitled “Power Distribution System,” each of which is incorporatedherein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to the field power distribution systems,and in particular to methods and apparatus related to a circuit boardhaving layered power filters in which the power filters can preclude orreduce unintended and/or intended transport of data from incoming oroutgoing power.

BACKGROUND

Some known electronic circuitry, compute devices, or communicationdevices can include power distribution systems that are intended tosolely distribute power. In some instances, however, electroniccomponents of the electronic circuitry around the power distributionsystems can induce data/information in the form of an electric orelectromagnetic signal into the power distribution systems. Known powerdistribution systems do not effectively filter an incoming power toreduce/mitigate such information/data being induced into the powerdistribution system and out of the electronic circuitry, compute devicesor communication devices. Thus, a need exists for power distributionsystems with layered power supply filters as described herein, thatimprove information security and/or operation reliability of theelectronic circuitry or digital processing systems.

SUMMARY

In some embodiments, a method includes receiving, at a circuit board, apower from a power supply. The method further includes filtering, at thecircuit board and via a power filter having at least three chokefilters, the power to produce a filtered power. The method furtherincludes dividing, at a first portion of a circuit on the circuit board,a power associated with the filtered power into a first power and asecond power, a characteristic of the first power differing from acharacteristic of the second power by a factor of at least 1.5 or atmost one half. In some embodiments, the method further includesdividing, at a second portion of the circuit, a power associated withthe second power into a third power and a fourth power, a characteristicof the third power differing from a characteristic of the fourth powerby a factor of at least 1.5 or at most one half.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram that illustrates a layered power filteringcircuit board, according to an embodiment.

FIG. 2 is a block diagram that illustrates a layered power filteringcircuit board, according to an embodiment.

FIG. 3 is a flowchart of a method for supplying filtered power,according to an embodiment.

DETAILED DESCRIPTION

Non-limiting examples of various aspects and variations of theembodiments are described herein and illustrated in the accompanyingdrawings.

One or more embodiments described herein generally relate to methods,apparatus, and systems that use a circuit board with layered powerfiltering to restrain the power supply from acting as an unintendedtransport medium for data, thus increasing security of data as well asrestricting data transport to an expected data transport medium.Generally, electronic devices, ranging from small embedded electronicdevices to large electronic systems can include a power distributionsystem and electronic circuitry near the power distribution systems as awhole, near individual components of the power distribution systems,and/or near individual power transport mediums of the power distributionsystem. In some instances, information from the electronic circuitry canbe unintentionally induced (e.g., electromagnetic induction) to thepower distribution system. Therefore, such power distribution systemscan potentially transport information via power transport mediums to anunintended recipient device (e.g., outside of and separate from theelectronic circuitry) and expose the information. Such unintendedtransport of information to power distribution systems and subsequentlypower transport mediums can be reduced or prevented using a circuitboard having the layered power filtering described herein.

Described herein are examples of circuit boards having layered powerfiltering that is suitable for highly secure and reliable computing,storage, and/or communication systems. One or more of the circuit boardshaving layered power filtering described herein include one or morepower filtering stages that can filter and change characteristics of aninput power from a power source (e.g., an untrusted power source or atrusted power source) at each filtering stage as an extra measure ofprotection in compromising environments. Moreover, one or more of thecircuit boards having layered power filtering described herein canreduce or prevent noise and other data induced from surroundingelectronic circuitry.

Electronic circuitry surrounding or near the one or more circuit boardsdescribed herein can generate noise in various electrostatic orelectromagnetic forms, or inadvertently share data across a set of powerlines powering the electronic circuitry and the one or more circuitboards. One or more of the circuit boards having layered power filteringdescribed herein can effectively power multiple such components in acommon closed spaces, compartments, or chassis.

FIG. 1 is a block diagram that illustrates circuit board 100 having alayered power filtering (also referred to herein as “the circuit board”or “layered power filtering circuit board”), according to an embodiment.The layered power filtering circuit board 100 can include a set ofelectric components mounted on a printed circuit board (PCB) that whenoperated precludes or reduces noise, ripple, and/or unintended data frompower supplied by a power supply 110. Power supply 110 can be, forexample, untrusted in the sense that the power supply is not controlledby the owner of the circuit board and may include or have access tomalicious or undesired components or entities. Alternatively, powersupply 110 can be, for example, trusted in the sense that the powersupply is controlled by the owner of the circuit board or another ownertrusted by the owner of the circuit board to not include malicious orundesired components or entities. The layered power filtering circuitboard 100 includes a port 120 that is connected to and/or operativelycoupled to the power supply 110 and receives a power from the powersupply 110. The layered power filtering circuit board 100 furtherincludes a power filter 130 disposed on the circuit board 100. The powerfilter 130 connects the port 120 to a power bus 140. The circuit board100 can further include a first circuit portion 151 and a second circuitportion 161 that collectively define a circuit 150. The differencecircuit portions 151, 161 can, for example, embody different functionsof a device. For example, circuit portion 151 can embody the circuitryfor a control plane of a router and circuit portion 161 can embody thecircuitry for a data plane of the router. The layered power filteringcircuit board 100 can be used in applications that use electroniccircuitry and/or electric power including, for example, computers, soundamplifiers, phones, laptops, servers, communication systems, routers,telecommunication appliances (e.g., firewalls), sensor arrays, vehicles,aircrafts, robots, spacecraft, satellites, cell towers, power stationsecurity, baseband communication equipment, radio systems (one way,two-way, and/or multipoint), networking equipment, physical security ofbuildings, and/or the like.

The circuit board 100 is a board that can mechanically support andelectrically interconnect electrical components (e.g., a capacitor(s), aresistor(s), an inductor(s) and/or the like) and/or electroniccomponents (a transistor(s), a diode(s), light emitting diodes, logicgate circuits, integrated circuits, and/or the like). The circuit board100 can further include conductive tracks (copper tracks, aluminumtracks, silver tracks, and/or the like), conductive sheets (coppersheets, aluminum sheets, and/or the like), insulating sheets (e.g.,porcelain sheets, mica sheets, plastic sheets, and/or the like), and/orthe like. In some instances, the circuit board 100 can include a powermanagement unit (PMU), a system management controller (SMC), a systembasis chip (SBC), and/or the like.

As mentioned above, the port 120 of the circuit board 100 is connectedto and/or operatively coupled to a power source 110 to receive power.The power source 110 can be, for example, a device that generates power(e.g., a motor-generator), coverts power (e.g., a coil transformer), ora medium that conducts the power (e.g., a wire). In some instances, thepower can be an alternating current (AC) electric power, a directcurrent (DC) electric power, an electromagnetic power, and/or the like.The power can have a set of characteristics such as, for example, avoltage, a wattage, a frequency, a current flow intensity, and/or thelike. In some instances, the power can include noises, ripples, and/orunintended information/data encoded in the power. In some instances, theunintended information/data can be induced by an electromagneticinduction of a signal propagating in a data transfer link close to thepower source 110 to the power from the power source 110. In someinstances, the unintended information/data can be induced from a databus connecting electronic circuitry within the circuit board 100 to apower cable providing electricity to an external electronic componentconnected to the circuit board 100.

The power filter 130 is disposed on the circuit board 100 and can beconfigured to receive the power from the power source 110 via the port120. The power filter 130 has at least three choke filters and canfilter the power to produce a filtered power. The at least three chokefilters can be connected together is series. In other words, the powerfilter 130 can produce power having a base voltage and a base frequencythat is provided to the power bus 120. The power filter 130 can beconnected to the power bus 120 and transmit the filtered power to thepower bus 120. One choke filter from the at least three choke filtersconnected in series (also referred to as the “last choke filter”) isalso connected directly to the power bus 120. For the last choke filter,the power just before the last choke filter has at least onecharacteristic that is different from at least one characteristic of thepower just after the last choke filter by a factor of at least 1.5 or atmost one half (e.g., a factor of 1.5, a factor of 2, a factor of 3, afactor of 5, a factor of 100, a factor of ⅓, a factor of ⅕, a factor of1/100, and/or the like). As described elsewhere herein, a set ofcharacteristics of the power can be, for example, a voltage, a wattage,a frequency, a current flow intensity, and/or the like. In someimplementations, the power filter 130 can be made of a set of electriccomponents such as a resistor(s), a capacitor(s), an inductor(s), and/orthe like that are connected by wires in series configuration and/or inparallel configuration to filter out noise, ripples, and/or unintendedinformation/data from the power. For example, in some instances, thepower filter 130 can include an active filter(s) (such as a shuntfilter(s), a series filter(s) and/or a hybrid filter(s)) and/or apassive filter(s) (such as shunt filter(s), a series filter(s), a hybridfilter(s), a single-tuned filter(s), a double-tuned filter(s), a dampedfilter(s), a low pass filter(s), a band pass filter(s), a high passfilter(s), a current limiter circuit(s), a voltage limiter circuit(s)),and/or the like.

The power bus 140 of the circuit board 100 is an electrical system thatcan include and interconnect several electric components such as, forexample, a generator(s), a load(s), and/or the like. The power bus 140can be disposed on the circuit 150 between and operatively coupled tothe power filter 130 and a first circuit portion 151 of the circuit 150.The power bus 140 can be configured to distribute the filtered power tovarious parts of the circuit 150 including the first sub-portion 152 ofthe first circuit portion 151 and the second sub-portion 153 of thefirst circuit portion 151. The power bus 140 can distribute the filteredpower to the first sub-portion 152 and the second sub-portion 153 at afirst point 156 and second point 157. The power bus 140 can be disposedon the circuit board 100 between and operatively coupled to the powerfilter 130 and an input point (not shown) of the circuit 150.

The circuit 150 includes a first circuit portion 151 and can furtherinclude a second circuit portion 161 that is mutually exclusive from thefirst circuit portion 151. The first circuit portion 151 includes afirst sub-portion 152 and a second sub-portion 153. The second circuitportion 161 includes a first sub-portion 162 and a second sub-portion163. The first sub-portion 152 of the first circuit portion 151, thesecond sub-portion 153 of the first circuit portion 151, the firstsub-portion 162 of the second circuit portion 161, and the secondsub-portion 163 of the second circuit portion 161 can each be configuredto perform a circuit function that operate best under a different set ofpower characteristics. For example the first sub-portion 152 of thefirst circuit portion can be configured to perform a set of powermanagement procedures using a power with 50 kHz frequency and 20 Voltspotential, while the second sub-portion 163 of the second circuitportion 161 can be configured to perform a set of signal communicationprocedures using a power with 100 kHz frequency and 200 Volts potential.

In some instances, the circuit 150 can be a power integrated circuit(PIC) that typically integrates a large number (e.g., tens, hundreds,thousands, millions, and/or the like) of electronic components (e.g.,metal-oxide-semiconductor (MOS) transistors, charged-coupled opticalsensor, floating-gate memory cell, and/or the like) made of asemiconductor(s) (e.g., silicon, silicon carbide, gallium arsenide,and/or the like), an insulator(s) (silicon oxide, silicon nitride,aluminum nitride, and/or the like), and/or a conductor(s) (silver,copper, indium tin oxide, and/or the like). The circuit can beconfigured to perform, for example, power management, dynamic voltagescaling, control procedures, arithmetic procedures, logical procedures,signal generation procedures, signal communication procedures,electronic charge storage procedures, and/or the like.

The first sub-portion 152 of the first circuit portion 151 receives afirst power from the first point 156, and the second sub-portion 153 ofthe first circuit portion 151 receives a second power from the secondpoint 157. The first sub-portion 162 of the second circuit portion 161receives a third power from the third point 166, and the secondsub-portion 163 of the second circuit portion 161 receives a fourthpower from the fourth point 167. In some implementations, the firstsub-portion 162 of the second circuit portion 161 receives the thirdpower from the first sub-portion 152 of the first circuit portion 151,and the second sub-portion 163 of the second circuit portion 161receives the fourth power from the second sub-portion 153 of the firstcircuit portion 151.

As shown in FIG. 1 , the input point receives the filtered power andconducts the filtered power to the first circuit portion 151. The firstcircuit portion 151 is disposed on the circuit 150 and between andoperatively coupled to the second circuit portion 161 and the inputpoint. The first circuit portion 151 receives a first power from theinput point at a first point 156 within the first circuit portion 151and a second power from the input point at a second point 157 within thefirst circuit portion 151. The first power has at least onecharacteristic that is different from at least one characteristic of thesecond power by a factor of at least 1.5 or at most one half (e.g., afactor of 1.5, a factor of 2, a factor of 3, a factor of 5, a factor of100, a factor of ⅓, a factor of ⅕, a factor of 1/100, and/or the like).

In some implementations, the second circuit portion 161 receives a thirdpower from the first circuit portion 151 at a third point 166 and afourth power from the first circuit portion 151 at a fourth point 167.The third power has at least one characteristic that is different fromat least one characteristic of the fourth power by a factor of at least1.5 or at most one half (e.g., a factor of 1.5, a factor of 2, a factorof 3, a factor of 5, a factor of 100, a factor of ⅓, a factor of ⅕, afactor of 1/100, and/or the like). Having different characteristics ineach of the first power, the second power, the third power, and thefourth power reduces/prevents data being passed over the power systemsof various portions and/or components of the circuit 150. Note that thisimplementation with the second circuit portion 161 is optional and notrequired for all embodiments. This implementation can be embodied wherethe first circuit portion 161 and the second circuit portion 162 are,for example, shielded separately for electromagnetic interference (EMI)and have separate access or authorization levels (e.g., the firstcircuit portion 161 can be governed by or associated with a first levelof access or authorization, while the second portion 161 can be governedby or associated with a second level of access or authorization that ismore restrictive than the first level of access or authorization).

In some instances, a characteristic of the first power is frequency anda characteristic of the second power is frequency, the frequency of thefirst power being at least twice the frequency of the second power. Forexample, the first power can have a frequency of 120 kHz that is largerthan a frequency of 40 kHz of the second power by a factor of 3. In someinstances, the characteristic of the first power is voltage and thecharacteristic of the second power is voltage, the voltage of the firstpower being at least twice the voltage of the second power. For example,the first power can have a voltage of 5 Volts that is smaller than avoltage of 100 Volts of the second power by a factor of 0.05.

In some instances, the characteristic of the first power includesfrequency and voltage, the characteristic of the second power includesfrequency and voltage. One of the voltage or the frequency of the firstpower can be at least twice the voltage or the frequency, respectively,of the second power. For example, the first power can have a frequencyof 50 kHz and a voltage of 5 Volts and the second power can have afrequency of 50 kHz that is the same frequency as the frequency of thefirst power and a voltage of 100 Volts that is larger than voltage ofthe first power by a factor of 20.

In some instances, the characteristic of the first power includesfrequency and voltage, the characteristic of the second power includesfrequency and voltage. Both the voltage and the frequency of the firstpower can be at least twice the voltage and the frequency, respectively,of the second power. For example, the first power can have a frequencyof 50 kHz and a voltage of 5 Volts and the second power can have afrequency of 100 kHz and a voltage of 10 Volts that are both larger thanthe frequency of the first power and the voltage of the first power by afactor of 2.

Note that while the circuit portions themselves are not components orcircuit portions solely dedicated to the function of power filtering,the different circuit portions can collectively act as a power filter(s)through their operation. More specifically, the frequency and/or voltagefor one circuit portion relative to the frequency and/or voltage foranother circuit portion within a given circuit can collectively act as apower filter when the frequency and/or voltage for the one circuitportion is at least twice or no more than half of the frequency and/orvoltage, respectively, for the other circuit portion. It is believedthat such an arrangement can act as a power filter due to reduction ofpassing of data over the power system between the two circuit portions.For example, when one circuit portion operates at a frequency of 50 kHzand the other circuit portion operates at a frequency of 100 kHz, theinstances of when the electromotive forces of both circuit portionsoverlap or synchronize are reduced due to the differing frequencies,which in turn reduces the extent to which data can pass over the powersystem between the two circuit portions. Similarly, when one circuitportion operates at a voltage of 5 Volts and the other circuit portionoperates at a voltage of 10 Volts, the electromotive forces from thehigher voltage obscures the electromotive forces from lower voltage,which in turn reduces the extent to which data can pass over the powersystem between the two circuit portions.

In some embodiments, a housing (not shown) can be used to further reduceinduction of noise or inductive information by electromagnetic effectsto the circuit board 100. The housing can include an enclosure that canalso help to protect and/or house various electronic components thatmake up the circuit board 100. For example, the housing can include aset of electromagnetic interference shields that reduces/blockselectromagnetic interference effects on the circuit board 100. In someembodiments, one or more components of the circuit board 100 can includeindividual housings that further protect each component frominterference and/or induction effects from the rest of components withinthe circuit board 100, or vice versa protect the rest of components frominterference and/or induction effects of each component.

The power filter 130 collectively with the frequency and/or voltage forone sub-portion (e.g., first sub-portion 152 or first sub-portion 162)relative to the frequency and/or voltage for another sub-portion (e.g.,second sub-portion 153 or second sub-portion 163) can be considered aslayers of power filtering of the circuit board 100. The power filter 130acts as a first power filter layer, produces a first set of filteredpower, and conducts the first set of filtered power to the power bus140. The first set of filtered power can be divided/distributed withdifferent voltage/frequency at the first point 156 and the second point157 acting as a second power filter layer to produce a second set offiltered power for operation of the first circuit portion 151. Thesecond set of filtered power can be divided/distributed with differentvoltage/frequency at the third point 166 and the fourth point 167 actingas a third power filter layer to produce a third set of filtered powerfor operation of the second circuit portion 161.

FIG. 2 is a block diagram that illustrates a circuit board 200 havinglayered power filtering (similar to the circuit board 100 shown anddescribed with respect to FIG. 1 ), according to an embodiment. Thecircuit board 200 includes an initial input filter 210, a power bus 220,and a set of electric and/or electronic components 250 (labeled“Protected Component Needing Power”) that operate when powered by power.The circuit board 200 can optionally include a set of secondary filters230 disposed between and operatively coupled to the power bus 220 andthe set of protected components 250. The layered power filtering circuitboard 200 can optionally include a set of tertiary filters 240 disposedbetween and operatively coupled to a subset of secondary filters fromthe set of secondary filters 230 and a set of more electric and/orelectronic components 260 (labeled “More Protected Component NeedingPower”). The layered power filtering described above can include atleast three choke filter.

The arrows shown between various components of the circuit board 200 inFIG. 2 represent conduction/flow of power between the variouscomponents. The initial input filter 210 receives power, via an inputport (not shown), from an untrusted or trusted power source (e.g., an ACpower socket of a building, an electric vehicle, an aircraft, and/or thelike), produces a first set of filtered power and conducts the first setof filtered power to the power bus 220. Each filtered power from thefirst set of filtered power from initial input filter 210 can have afirst set of characteristics (e.g., a frequency, a voltage, a peakpotential, and/or the like). The power bus 220 can distribute the firstset of filtered power between the set of electric and/or electroniccomponents 250 (e.g., a set of circuits).

The set of secondary filters 230 can further filter the first set offiltered power to produce a second set of filtered power having a secondset of characteristics, and conduct the second set of filtered power tothe set of components 250. In some implementations, the set of tertiaryfilters 240 can further filter a subset of the second set of filteredpower to produce a third set of filtered power having a third set ofcharacteristics, and conduct the third set of filtered power to the setof more components 260.

In some implementations, the circuit board 200 can include a set ofoutput ports (not shown) that receive filtered/clean power from thefirst set of filtered power of the power bus 220 and providefiltered/clean power to an external device (e.g., a peripheral device,an extension board, and/or the like). In some instances, a secondaryfilter from the set of secondary filters can be disposed between andoperatively coupled to the power bus 220 and the output port. In someinstances, a tertiary filter from the set of tertiary filters 240 can bedisposed between and operatively coupled to a secondary filter from theset of secondary filters 230 and the set of more components 260.

In some instances, each filter from the initial input filter 210, theset of secondary filters 230, and the set of tertiary filters 240 can beconfigured to change characteristics (e.g., frequency, voltage, and/orthe like) of an incoming power in addition to filtering the incomingpower. Therefore, each filter produces a filtered power that has lessnoise and different characteristics compared to its correspondingincoming power.

In some embodiments, the layered power filtering of FIG. 1 and FIG. 2can be implemented on a set of circuit boards instead of one circuitboard. In one example with respect to FIG. 2 , each secondary filterfrom the set of secondary filters and/or each component from the set ofelectric and/or electronic components 250 can be mounted on a separatecircuit board.

FIG. 3 is a flowchart of a method 300 for supplying filtered power,according to an embodiment. The method 300 can be implemented/performedby a circuit board having layered power filtering (similar to thecircuit board 100 shown and described with respect to FIG. 1 ). At 301,the circuit board receives a power from an untrusted or trusted powersupply. At 302, the circuit board filters the power to produce afiltered power. The filtering of power can be achieved by a power filter(similar to the power filter 130 as shown and described with respect toFIG. 1 ) made of a set of electric components such as a resistor(s), acapacitor(s), an inductor(s), and/or the like that are connected bywires in series configuration and/or in parallel configuration to filterout noise, ripples, and/or unintended information/data from the power.

At 303, the layered power filtering circuit board divides, at a firstportion of the circuit board, a power associated with the filtered powerinto a first power and a second power. A characteristic of the firstpower differs from a characteristic of the second power by a factor ofat least 1.5 or at most one half. At 304, the circuit board divides, ata second portion of the circuit board, a power associated with thesecond power into a third power and a fourth power. A characteristic ofthe third power can differ from a characteristics of the fourth power bya factor of at least 1.5 or at most one half.

It should be understood that the disclosed embodiments are not intendedto be exhaustive, and functional, logical, operational, organizational,structural and/or topological modifications may be made withoutdeparting from the scope of the disclosure. As such, all examples and/orembodiments are deemed to be non-limiting throughout this disclosure.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

Examples of computer code include, but are not limited to, micro-code ormicro-instructions, machine instructions, such as produced by acompiler, code used to produce a web service, and files containinghigher-level instructions that are executed by a computer using aninterpreter. For example, embodiments can be implemented using Python,Java, JavaScript, C++, and/or other programming languages anddevelopment tools. Additional examples of computer code include, but arenot limited to, control signals, encrypted code, and compressed code.

The drawings primarily are for illustrative purposes and are notintended to limit the scope of the subject matter described herein. Thedrawings are not necessarily to scale; in some instances, variousaspects of the subject matter disclosed herein can be shown exaggeratedor enlarged in the drawings to facilitate an understanding of differentfeatures. In the drawings, like reference characters generally refer tolike features (e.g., functionally similar and/or structurally similarelements).

The acts performed as part of a disclosed method(s) can be ordered inany suitable way. Accordingly, embodiments can be constructed in whichprocesses or steps are executed in an order different than illustrated,which can include performing some steps or processes simultaneously,even though shown as sequential acts in illustrative embodiments. Putdifferently, it is to be understood that such features may notnecessarily be limited to a particular order of execution, but rather,any number of threads, processes, services, servers, and/or the likethat may execute serially, asynchronously, concurrently, in parallel,simultaneously, synchronously, and/or the like in a manner consistentwith the disclosure. As such, some of these features may be mutuallycontradictory, in that they cannot be simultaneously present in a singleembodiment. Similarly, some features are applicable to one aspect of theinnovations, and inapplicable to others.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range is encompassed within the disclosure. That the upper andlower limits of these smaller ranges can independently be included inthe smaller ranges is also encompassed within the disclosure, subject toany specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the disclosure.

The phrase “and/or,” as used herein in the specification and in theembodiments, should be understood to mean “either or both” of theelements so conjoined, i.e., elements that are conjunctively present insome cases and disjunctively present in other cases. Multiple elementslisted with “and/or” should be construed in the same fashion, i.e., “oneor more” of the elements so conjoined. Other elements can optionally bepresent other than the elements specifically identified by the “and/or”clause, whether related or unrelated to those elements specificallyidentified. Thus, as a non-limiting example, a reference to “A and/orB”, when used in conjunction with open-ended language such as“comprising” can refer, in one embodiment, to A only (optionallyincluding elements other than B); in another embodiment, to B only(optionally including elements other than A); in yet another embodiment,to both A and B (optionally including other elements); etc.

As used herein in the specification and in the embodiments, “or” shouldbe understood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the embodiments, “consisting of,” will refer to the inclusion ofexactly one element of a number or list of elements. In general, theterm “or” as used herein shall only be interpreted as indicatingexclusive alternatives (i.e., “one or the other but not both”) whenpreceded by terms of exclusivity, such as “either,” “one of” “only oneof” or “exactly one of.” “Consisting essentially of,” when used in theembodiments, shall have its ordinary meaning as used in the field ofpatent law.

As used herein in the specification and in the embodiments, the phrase“at least one,” in reference to a list of one or more elements, shouldbe understood to mean at least one element selected from any one or moreof the elements in the list of elements, but not necessarily includingat least one of each and every element specifically listed within thelist of elements and not excluding any combinations of elements in thelist of elements. This definition also allows that elements canoptionally be present other than the elements specifically identifiedwithin the list of elements to which the phrase “at least one” refers,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, “at least one of A and B” (or,equivalently, “at least one of A or B,” or, equivalently “at least oneof A and/or B”) can refer, in one embodiment, to at least one,optionally including more than one, A, with no B present (and optionallyincluding elements other than B); in another embodiment, to at leastone, optionally including more than one, B, with no A present (andoptionally including elements other than A); in yet another embodiment,to at least one, optionally including more than one, A, and at leastone, optionally including more than one, B (and optionally includingother elements); etc.

In the embodiments, as well as in the specification above, alltransitional phrases such as “comprising,” “including,” “carrying,”“having,” “containing,” “involving,” “holding,” “composed of,” and thelike are to be understood to be open-ended, i.e., to mean including butnot limited to. Only the transitional phrases “consisting of” and“consisting essentially of” shall be closed or semi-closed transitionalphrases, respectively, as set forth in the United States Patent OfficeManual of Patent Examining Procedures, Section 2111.03.

What is claimed is:
 1. An apparatus, comprising: a circuit boardconfigured to be coupled via a port of the circuit board to a powersupply external and separate from the circuit board; a circuit disposedon the circuit board, the circuit including a first circuit componentand a second circuit component; a first power filter operatively coupledto and between (1) the port and (2) the first circuit component and thesecond circuit component; a second power filter operatively coupled toand between the first power filter and the first circuit component, thefirst circuit component configured to receive a first power from thesecond power filter; and a third power filter operatively coupled to andbetween the first power filter and the second circuit component, thesecond circuit component configured to receive a second power from thethird power filter.
 2. The apparatus of claim 1, wherein the first powerfilter is a first choke filter, the second power filter is a secondchoke filter, and the third power filter is a third choke filter.
 3. Theapparatus of claim 1, wherein a characteristic of the first power isfrequency and a characteristic of the second power is frequency, thefrequency of the first power being at least 1.5 or at most one half thefrequency of the second power.
 4. The apparatus of claim 1, wherein acharacteristic of the first power is voltage and a characteristic of thesecond power is voltage, the voltage of the first power being at least1.5 or at most one half the voltage of the second power.
 5. Theapparatus of claim 1, wherein a characteristic of the first powerincludes frequency and voltage, a characteristic of the second powerincludes frequency and voltage, one of the voltage or the frequency ofthe first power being at least 1.5 or at most one half the voltage orthe frequency, respectively, of the second power.
 6. The apparatus ofclaim 1, wherein a characteristic of the first power includes frequencyand voltage, a characteristic of the second power includes frequency andvoltage, the voltage and the frequency of the first power being at least1.5 or at most one half the voltage and the frequency, respectively, ofthe second power.
 7. The apparatus of claim 1, further comprising: apower bus disposed on the circuit board, the power bus operativelycoupled to and disposed between (1) the first power filter and (2) thefirst circuit component and the second circuit component.
 8. Theapparatus of claim 1, further comprising: a fourth power filteroperatively coupled to and between the first power filter and the thirdpower filter.
 9. A method, comprising: receiving, at a circuit board andvia a power filter, a first power from a power supply; filtering, at thecircuit board, the first power to produce a second power; filtering, ata first portion of a circuit on the circuit board, a power associatedwith the second power to produce a third power; and filtering, at asecond portion of the circuit mutually exclusive of the first portion ofthe circuit, a power associated with the second power to produce afourth power, a characteristic of the third power differing from acharacteristic of the fourth power by a factor of at least 1.5 or atmost one half.
 10. The method of claim 9, wherein: the characteristic ofthe third power is frequency and the characteristic of the fourth poweris frequency, the frequency of the third power being at least twice thefrequency of the fourth power.
 11. The method of claim 9, wherein: thecharacteristic of the third power is voltage and the characteristic ofthe third power is voltage, the voltage of the second power being atleast twice the voltage of the third power.
 12. The method of claim 9,wherein: the characteristic of the third power includes frequency andvoltage, the characteristic of the fourth power includes frequency andvoltage, one of the voltage or the frequency of the third power being atleast twice the voltage or the frequency, respectively, of the fourthpower.
 13. The method of claim 9, wherein: the characteristic of thethird power includes frequency and voltage, the characteristic of thefourth power includes frequency and voltage, the voltage and thefrequency of the third power being at least twice the voltage and thefrequency, respectively, of the fourth power.
 14. The method of claim 9,wherein the power filter includes at least three choke filters.
 15. Anapparatus, comprising: a circuit including a first circuit component anda second circuit component, the circuit configured to receive power thathas been filtered by a first power filter and that has been receivedfrom a power source; a second power filter operatively coupled to andbetween the first power filter and the first circuit component, thefirst circuit component configured to receive a first power from thesecond power filter; and a third power filter operatively coupled to andbetween first power filter and the second circuit component, the secondcircuit component configured to receive a second power from the thirdpower filter.
 16. The apparatus of claim 15, further comprising: acircuit board including a port, the circuit being disposed on thecircuit board, the port of the circuit board operatively coupled to thecircuit and configured to receive the power from the power source. 17.The apparatus of claim 15, wherein a characteristic of the first poweris frequency and a characteristic of the second power is frequency, thefrequency of the first power being at least 1.5 or at most one half thefrequency of the second power.
 18. The apparatus of claim 15, wherein acharacteristic of the first power is voltage and a characteristic of thesecond power is voltage, the voltage of the first power being at least1.5 or at most one half the voltage of the second power.
 19. Theapparatus of claim 15, wherein a characteristic of the first powerincludes frequency and voltage, a characteristic of the second powerincludes frequency and voltage, one of the voltage or the frequency ofthe first power being at least 1.5 or at most one half the voltage orthe frequency, respectively, of the second power.
 20. The apparatus ofclaim 15, wherein a characteristic of the first power includes frequencyand voltage, a characteristic of the second power includes frequency andvoltage, the voltage and the frequency of the first power being at least1.5 or at most one half the voltage and the frequency, respectively, ofthe second power.